[Boost-users] Data type to handle C++ and Boost streams?

Hi all, Bit of a basic question - I'd like to have some functions that work with files (using std::fstream) but can also handle boost::iostreams. Is there a data type I can use that can handle both? For example: void writeSomeData(std::fstream out); I can't pass a boost::iostream::stream to this function. What type can I use to achieve this? Many thanks, Adam.